Conventionally, as a coil configuration for an armature for rotary electric machine, a configuration is proposed in which a portion where a coil in a lower layer and a coil in an upper layer that are adjacent are wound in a crossed manner is located on side surfaces of each tooth, that are opposed to the adjacent teeth.
In this configuration, on such side surfaces opposed to the adjacent teeth, a coil is wound with feed by ½ pitch of the wire diameter, thereby forming a cross portion.
Thus, cross portions are located on two side surfaces of each tooth opposed to side surfaces of the adjacent teeth so that the coil shape becomes substantially a symmetrical shape, thereby obtaining a coil that is excellent in terms of assembly workability, outer appearance, and high-speed winding (for example, Patent Document 1).
However, the space factor of coil is low because conductive wires overlap at the cross portion of coils.
Considering the above, a coil configuration for an armature that cross portions of coils are collectively located on a surface on one side in the circumferential direction of each tooth, and a coil is wound in a regularly aligned manner on a side surface on the other side in the circumferential direction of each tooth, that is opposed to said tooth, is proposed as shown in Patent Document 2.
In Patent Document 2, a coil is sequentially wound in a spiral shape so as to be fed from one end to the other end in the radial direction of each tooth and then returned from the other end to the one end, and such winding is repeated, whereby cross portions are collectively located on a one-side surface of each tooth. Thus, a surface on which a conductive wire of a coil is regularly aligned and a surface on which the height of stacking is increased due to presence of cross portions are paired between the adjacent teeth, whereby the teeth compensate each other's space and high-density coils are formed.
In Patent Document 3, a coil bobbin attached to each tooth has a winding frame portion on which a conductive wire of a coil is wound, and a plurality of protrusions protruding from the winding frame portion, which are provided on at least a corner portion of an angle portion of the coil bobbin, so that a conductive wire is wound so as to be fitted into the resultant groove.